1. Field of Invention
The present invention relates to a heater cartridge and a molding apparatus having the same. More particularly, the present invention relates to a heater cartridge for uniformly heating a mold and a molding apparatus having the same.
2. Description of the Related Art
Generally, a molding apparatus injects a forming material into a mold having a predetermined shape to obtain a formed object having a predetermined shape. A molding process, that uses the molding apparatus, includes a plurality of stages. The molding process includes a heating stage for heating an area such as a cavity of the mold before injecting a forming material, and a cooling stage for cooling a formed object after injecting the forming material. The heating stage uses heated steam, heated water, and the like as a heat source.
The molding apparatus includes an upper mold moving upward and downward, a lower mold coupled to the upper mold, and a cavity formed by coupling of the upper mold and the lower mold so that a predetermined object is formed therein. The molding apparatus includes an injection unit formed with an injection hole through which a forming material such as resin is injected, and a flowing runner guiding the forming material from the injection hole to the cavity. The molding apparatus includes a heating part inserted to a cartridge channel formed through an inside of the upper and lower molds to heat the cavity. Thus, the forming material injected in the flowing runner and the cavity maintains a predetermined temperature to have fluidity. The molding apparatus includes a cooling channel, separately provided with respect to the heating part, inside the mold to cool a formed object after the forming material is completely injected, and a cooling medium pump circulating a cooling medium through the cooling channel.
The heating part heats the cavity and the flowing runner to have a predetermined temperature. Then, the forming material is injected from the injection unit to the cavity through the flowing runner. The heating of the cavity reduces a temperature difference between the forming material and the cavity which enhances the fluidity of the forming material and prevents the forming material from being rapidly cooled. Thus, inferiority thereof is reduced. After injection of the forming material is completed, the cooling medium pump circulates the cooling medium through the cooling channel to cool the formed object. Then, the upper and lower molds are separated, and the formed object is obtained from the cavity.
However, in the conventional molding apparatus, since the heating part heats the cavity and the flowing runner irrespective of the distance from the cavity or the flowing runner, the cavity is unevenly heated according to the distance from the heating part. Also, since the cartridge channel heated by the heater cartridge and the cooling channel are separately formed, the configuration thereof is complicated, and needs more installation space. Also, since the heating interferes with the cooling, the respective efficiencies thereof are deteriorated. Also, the conventional molding apparatus uses petroleum, and the like to obtain heated steam or heated water, thereby having a low thermal efficiency and needing a long heating time.
Accordingly, there is a need for an improved heater cartridge and molding apparatus using the same.